Believe it or not, a standard sandwich bag works wonders as a head for getting pull string through pipe with a vacuum. On the jobsite, it's a common item, considering most workers bring their lunch to work with them. Baggies work better than a foam mouse in smaller pipe, you just have to make sure you don't stuff it in the pipe.
If you have a big pull, you start by vacuuming in a smaller line, like jet-line, and use that to pull in larger diameter line. For the biggest pulls, we've had to go from jet-line to 1/4" poly line to as much as 1" rope to get the right size pull line in the conduit. By then, you've moved to using a tugger to pull the wire in.
“Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain
Diapers and Politicians need to be changed often... Usually for the same reason.